Agricultural actives, such as pesticides and plant growth regulators, have conventionally been provided to the end-user in different concentrated forms to be diluted in water or other suitable medium to a dilute ready-to-use formulation by the end-user. Such concentrated forms include solid formulations, e.g. powders, and liquid formulations. In many applications, liquid formulations are preferred as problems of dusting of toxic powders and slow dissolution in the diluent may be avoided.
The liquid concentrated formulations include so-called emulsion concentrates and soluble liquid concentrates. An emulsion concentrate comprises an agricultural active, a water-insoluble solvent, and an emulsifier, and when added to the water, it spontaneously, or after mixing, forms an oil-in-water emulsion, the agricultural active primarily being present in the emulsion droplets. This type of concentrated formulation is especially suitable for agricultural actives that are water insoluble/have low water solubility, and where the recommended concentration in the ready-to-use formulation exceeds the solubility of the agricultural active.
A soluble liquid concentrate comprises a water-soluble solvent and agricultural active, and when added to the water, spontaneously, or after mixing, both the solvent and the agricultural active dissolve in the water. This type of concentrated formulation is especially suitable for agricultural actives that are soluble in water also at concentrations exceeding the recommended concentration in the ready-to-use formulation.
When mixing a soluble liquid concentrate with an aqueous medium, initially, there will be a high local concentration of the active before the resulting formulation is equilibrated. Hence, there is a risk for precipitation of the agricultural active occurring when diluting the soluble liquid concentrate in an aqueous medium. This precipitation may pose problems due to slow dissolution of the precipitates. In some cases even, the precipitates are essentially water-insoluble.
WO2007/028518 discloses a soluble liquid formulation of imidacloprid, a neonicotinide insecticide, where N-methyl pyrrolidone (NMP) is used as solvent.
However, NMP has been shown to be a reproductive toxicant (Merlet, S. et al, “Green Solvents for Agrochemicals”, Adjuvant Newsletter, vol 7, Issue 2, February 2010, pages 1-3).
One approach to address the problems connected to the use of NMP in Agricultural formulations is described in WO2008/101620, where dialkylamides containing a hydroxysubstituted acyl radical is proposed as a solvent for biocides.
As reported by Merlet, S. et al (supra) however, the solubility of certain commercially interesting biocides, like Imidacloprid, does not have a very high solubility in such dialkylamides containing hydroxysubstituted acyl radicals.
Hence, there is a need in the art to find solvents that can replace NMP in soluble liquid formulations for agricultural actives, while maintaining high solubility of the agricultural actives.